1. Field of the Invention
The present invention relates to a method for forming salicide in a semiconductor device, and more particularly to a method for forming salicide in a semiconductor device, which can selectively and simultaneously form salicide region (or Co-salicide region) and a non-salicide region (or non-Co-salicide in a one-chip semiconductor device.
2. Description of the Prior Art
The conventional method for forming salicide in a semiconductor device will be described as follows with reference to FIGS. 1A through 1E.
FIGS. 1A through 1E are cross-sectional views showing a conventional process of forming salicide in a semiconductor device.
According to a conventional salicide forming method of a semiconductor device, as shown in FIG. 1A, a gate oxide film 13 and a gate electrode 15 are sequentially formed on a silicon substrate 11 including a non-salicide region and a salicide region. Then, an LDD spacer 17 is formed on one side of the gate oxide film 13 and the gate electrode 15.
Next, as shown in FIG. 1B, an oxide film 19 is deposited on the upper surface of the resultant structure obtained through the above process, and then a photosensitive material layer 21 or a bottom anti-reflective coating (BARC) is formed in the non-salicide region A of the substrate. The oxide film 19 serves later as a barrier oxide film which prevents the generation of salicide in the non-salicide region during a salicide generating process.
Subsequently, as shown in FIG. 1C, an etch-back process is performed to the photosensitive material layer 21, and the photosensitive material layer 21 is removed. When the etch-back process of the photosensitive material layer 21 is performed, activated plasma, such as CHF3/CF4/O2/Ar, and the likes, is used. In addition, N2 gas, CxFy gas, such as C4F8, C2F6, and C5F8, and the likes can be used. Also, while the etch-back process of the photosensitive material layer 21 is performed, an etching process progresses to the oxide film 19 located on the gate electrode 15 so that there is no residual oxide film on the gate electrode 15.
Next, as shown in FIG. 1D, a photosensitive pattern 23 is formed on the non-salicide region A. Then, after the oxide film 19 located in the salicide region B of the substrate is selectively removed using the photosensitive pattern 23 as a mask, the photosensitive pattern 23 is removed. At this time, etching of a portion of the oxide film 19 is performed using activated plasma of CHF3/CF4/O2/Ar, etc. In addition, N2 gas and CxFy gas, such as C4F8, C2F6, and C5F8, and the likes can be used.
Subsequently, as shown in FIG. 1E, salicide (or Co-salicide) 25 is formed on the exposed portion of the gate electrode 15 in the non-salicide region A, and on the exposed portions of the silicon substrate 11 and the gate electrode 15 in the salicide region B. At this time, in the non-salicide part, salicide (or Co-salicide) is not generated due to a residual oxide barrier.
In accordance with the conventional method described above, -after an LDD structure is formed, an oxide film formed in the salicide region is removed by using a photosensitive pattern as a barrier. Subsequently, after the photosensitive pattern is removed, a salicide layer is formed, so that steps of the salicide forming process are increased.